The Evolution of Stellar Mass Density and its Implied Star Formation History

TL;DR

This paper compares stellar mass density measurements with star formation indicators across redshifts, revealing discrepancies at z=3 possibly due to measurement errors or evolving stellar initial mass functions.

Contribution

It provides a comprehensive analysis of stellar mass density evolution and its implications for the cosmic star formation history, highlighting inconsistencies at high redshift.

Findings

Good agreement between star formation histories at z<0.7

Discrepancies at z=3 with higher instantaneous star formation rates

Potential explanations include dust extinction, measurement errors, or evolving initial mass function

Abstract

Using a compilation of measurements of the stellar mass density as a function of redshift we can infer the cosmic star formation history. For z < 0.7 there is good agreement between the two star formation histories. At higher redshifts the instantaneous indicators suggest star formation rates larger than that implied by the evolution of the stellar mass density. This discrepancy peaks at z = 3 where instantaneous indicators suggest a star formation rate around 0.6 dex higher than those of the best fit to the stellar mass history. We discuss a variety of explanations for this inconsistency, such as inaccurate dust extinction corrections, incorrect measurements of stellar masses and a possible evolution of the stellar initial mass function.